you have to be stern to avoid them coming back. We had a lady (who i am sure saw us moving in) knock the night we moved in. i told her very sternly that my porch was not outside the metro stop or a street corner. That she has no right to solicit from me here. go way and dont come back.
You having cash on you or not is not relevant. It is your cash and your house. its not okay for people to come to your house and ask you for your money.